Devices and methods for inter-vertebral orthopedic device placement

ABSTRACT

A spinal implant device includes a spacer region and an attachment region. The spacer region is adapted to be positioned between first and second spinous processes of first and second vertebral bodies to limit movement of the first spinous process and the second spinous process toward one another. The attachment region attaches to the first spinous process via a fastener that extends substantially along a long axis of the spinous process.

REFERENCE TO PRIORITY DOCUMENT

This application is a continuation of U.S. patent application Ser. No.11/613,146, filed Dec. 19, 2006, now U.S. Pat. No. 8,002,802 entitled“Devices and Methods for Inter-vertebral Orthopedic Device Placement,”which claims the benefit of priority of the following U.S. ProvisionalPatent Applications: (1) U.S. Provisional Patent Application Ser. No.60/751,509, filed Dec. 19, 2005; (2) U.S. Provisional Patent ApplicationSer. No. 60/763,411, filed Jan. 30, 2006; (3) U.S. Provisional PatentApplication Ser. No. 60/792,378, filed Apr. 14, 2006; (4) U.S.Provisional Patent Application Ser. No. 60/815,296, filed Jun. 20, 2006;(5) U.S. Provisional Patent Application Ser. No. 60/815,956, filed Jun.24, 2006; and (6) U.S. Provisional Patent Application Ser. No.60/834,209, filed Jul. 27, 2006. Priority of the aforementioned filingdates is hereby claimed and the disclosures of the Applications arehereby incorporated by reference in their entirety.

BACKGROUND

The present disclosure is related to orthopedic devices implantedbetween skeletal segments. The implanted devices are used to adjust andmaintain the spatial relationship(s) of adjacent bones. Depending on theimplant design, the motion between the skeletal segments may be returnedto normal, increased, modified, limited or completely immobilized.

Progressive constriction of the central canal within the spinal columnis a predictable consequence of aging. As the spinal canal narrows, thenerve elements that reside within it become progressively more crowded.Eventually, the canal dimensions become sufficiently small so as tosignificantly compress the nerve elements and produce pain, weakness,sensory changes, clumsiness and other manifestation of nervous systemdysfunction.

Constriction of the canal within the lumbar spine is termed lumbarstenosis. This condition is very common in the elderly and causes asignificant proportion of the low back pain, lower extremity pain, lowerextremity weakness, limitation of mobility and the high disability ratesthat afflict this age group.

The traditional treatment for this condition has been laminectomy, whichis the surgical removal of the bone and ligamentous structures thatconstrict the spinal canal. Despite advances in surgical technique,spinal decompression surgery can be an extensive operation with risks ofcomplication from the actual surgical procedure and the generalanesthetic that is required to perform it. Since many of these elderlypatients are in frail health, the risk of developing significantperi-operative medical problems remains high. In addition, the surgicalresection of spinal structures may relieve the neural compression butlead to spinal instability in a substantial minority of patients. Thatis, removal of the spinal elements that compress the nerves may weakenthe vertebral column and lead to spinal instability and vertebralmal-alignment. With instability, the vertebrae will move in an abnormalfashion relative to one another and produce pain, nerve re-impingement,weakness and disability. Further, re-stabilization of the spinal columnrequires additional and even more extensive surgery. Because of theseissues, elderly patients with lumbar stenosis must often choose betweenliving the remaining years in significant pain or enduring the potentiallife-threatening complications of open spinal decompression surgery.

Recently, lumbar stenosis has been treated by the distraction—instead ofresection—of those tissues that compress the spinal canal. In thisapproach, an implantable device is placed between the spinous processesof the vertebral bodies at the stenotic level in order to limit theextent of bone contact during spinal extension. Since encroachment uponthe nerve elements occurs most commonly and severely in extension, thistreatment strategy produces an effective increase in the size of thespinal canal by limiting the amount of spinal extension. In effect, thedistraction of the spinous processes changes the local bony anatomy anddecompresses the nerves at the distracted level by placing the spinalsegment into slight flexion.

A number of devices that utilize this strategy have been disclosed. U.S.Pat. Nos. 6,451,020; 6,695,842; 5,609,634; 5,645,599; 6,451,019;6,761,720; 6,332,882; 6,419,676; 6,514,256; 6,699,246 and otherillustrate various spinous process distractors. Unfortunately, theplacement of all devices requires surgical exposure of the posterior andlateral aspects of the spinous processes as well as the posterior aspectof the spinal column. Thus, these operations still carry a significantrisk of peri-operative complications in this frail patient population.

SUMMARY

This application discloses a series of novel inter-spinous implants andmethods of minimally invasive placement. Bone fasteners are placed intoeach of the two spinous processes at the level of implantation. Adistractor is used to separate the spinous processes and the implant isplaced between the distracted processes. In order to standardize theprocedure across patients and between different surgeons, the distractorincludes an indicator that can measure the applied force of distraction.After distraction, a limited decompression of the nerve elements may bepreformed, if desired, by removal of a small segment of the inferioraspect of the superior lamina and of the inferior facet surface of thesuperior vertebra as well as a small segment of the superior aspect ofthe inferior lamina and of the superior facet surface of the inferiorvertebra.

After distraction and possible limited nerve decompression, an implantis placed between the adjacent spinous processes and used to maintainthem in the distracted position. The implant is anchored to one or morespinous processes by bone screws or similar fasteners and functions tolimit the extent of vertebral extension at the implanted level. Afterthe implant is positioned, the distractor and distraction screws areremoved. In one embodiment, a distraction screw disassembles intocomponent members and one component serves as the fastener that attachesthe implant onto bone. Multiple embodiments of the implant areillustrated.

Devices that engage and anchor into the spinous process of each of twoadjacent vertebras are also illustrated. In addition to limitingvertebral extension, these devices will control the total extent ofrelative vertebral motion in one or more planes at the implanted level.Several embodiments of these interspinous devices are disclosed.Combination implants are also illustrated.

In one aspect, there is disclosed a spinal implant device, comprising: aspacer region adapted to be positioned between first and second spinousprocesses of first and second vertebral bodies to limit movement of thefirst spinous process and the second spinous process toward one another;and an attachment region attached to the spacer region, the attachmentregion adapted to attach to the first spinous process via a fastenerthat extends substantially along a long axis of the spinous process.

In another aspect, there is disclosed a spinal implant device,comprising: a first attachment region that attaches to a first spinousprocess via a fastener that extends substantially along a long axis ofthe first spinous process; and a second attachment region that attachesto a second spinous process, wherein the first attachment region and thesecond attachment region can move a limited distance toward one anotherand a limited distance away from one another to limit relative movementbetween the first and second spinous processes.

In another aspect, there is disclosed a spinal implant device,comprising: a plate having a first attachment region that attaches to afirst spinous process and a second attachment region that attaches to asecond spinous process, the plate further having a spacer region betweenthe first and second attachment regions, the spacer region adapted topermit relative movement between the first and second attachmentregions.

In another aspect, there is disclosed a method of stabilizing the spine,comprising: attaching a first portion of a spinal implant to a firstspinous process of a first vertebral body wherein the first portion ofthe spinal implant is attached to the long axis of the first spinousprocess; and attaching a second portion of the spinal implant to asecond spinous process of a second vertebral body, wherein the spinalimplant limits movement of the first spinous process relative to thesecond spinous process.

In another aspect, there is disclosed a method of stabilizing the spine,comprising: fastening a first distraction member to a first spinousprocess of a first vertebral body wherein the distraction screw extendsalong a long axis of the first spinous process; attaching a seconddistraction member to a second spinous process of a second vertebralbody; distracting the first and second spinous processes using the firstand second distraction members; and placing an implant between the firstand second spinous processes wherein the implant modulates relativemovement between the first and second spinous processes.

In another aspect, there is disclosed method of stabilizing the spine,comprising: removing a segment of the inferior aspect of the superiorlamina and a segment of the inferior facet surface of the superiorvertebra; removing a segment of the superior aspect of the inferiorlamina and a segment the superior facet surface of the inferiorvertebra; and placing an implant between the superior lamina and thesuperior vertebra.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising an attachment region adapted toattach to a first spinous process via a fastener that extendssubstantially along a long axis of the spinous process.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising an attachment region adapted toattach to a first spinous process via a fastener that extendssubstantially along a long axis of the lamina.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising an attachment region adapted toattach to a first spinous process via a fastener that extends toward amidline of the lamina.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising an attachment region adapted toattach to a first spinous process via a fastener that extends toward asuperior aspect of the midline of the lamina.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising an attachment region adapted toattach to a first spinous process by clamping onto sides of the laminaon both sides of the vertebral midline.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising a first segment that attachesto a first vertebral body; a second segment that attaches to a secondvertebral body, the first and second segments being movable relative toone another to vary the length of the spinal implant; and a spacerregion that positions between first and second spinous processes of thefirst and second vertebral bodies.

In another aspect, there is disclosed a spinal implant device forcontrolling vertebral motion, comprising a spring formed of a coiled,elongated member, the spring extending along an axis and adapted to bepositioned between a pair of spinous processes, wherein a first end ofthe elongate member attaches to a first spinous process and a second endattaches to a second spinous process.

The implants described provide dynamic spinal stabilization whilepermitting minimally invasive placement. Other features and advantageswill be apparent from the following description of various embodiments,which illustrate, by way of example, the principles of the discloseddevices and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a device that is configured forplacement between the spinous processes of two adjacent vertebralbodies.

FIG. 2 shows perspective, top, front, and side views of the device ofFIG. 1.

FIG. 3 shows a pair of devices at adjacent vertebral segments.

FIGS. 4A-4D show another embodiment of the device wherein the deviceincludes a cavity for receipt of a bone graft or segment.

FIG. 5 shows the device of FIGS. 4A-4D attached onto the spinous processbetween vertebral bodies.

FIG. 6A shows distraction screws prior to being attached to the spinousprocesses of the vertebral bodies

FIG. 6B shows distraction screws attached to the spinous processes ofthe vertebral bodies and a distractor device mounted on the distractorscrews.

FIG. 7A shows the device positioned between the vertebral bodies withthe distraction screws still attached to the vertebral bodies.

FIG. 7B shows the device positioned between the vertebral bodies with aportion of the distraction screw extending upwardly through an opening.

FIG. 8 shows a lock nut locking the device to a vertebral body.

FIG. 9 shows an enlarged view of a portion of the distractor device.

FIG. 10 shows an enlarged, cross-sectional view of a portion of thedistractor device.

FIGS. 11A and 11B illustrate an optional step within the implantationprocedure.

FIGS. 12A, 12B, and 13 illustrate an additional embodiment wherein theimplant can expand and vary in size.

FIGS. 14A to 18B illustrate two additional mechanisms that will produceexpandable implants.

FIGS. 19-21 show another embodiment of an expandable implant.

FIG. 22 shows another embodiment of an implant.

FIG. 23 shows yet another embodiment of an interspinous device.

FIG. 24 shows another embodiment of the interspinous device that permitsrelative movement between the vertebral bodies.

FIG. 25 shows another embodiment of an interspinous device that includesfirst and second attachment regions that are movably attached to oneanother.

FIGS. 26A and 26B show exploded and cross-sectional views of the deviceof FIG. 25.

FIG. 27 shows yet another embodiment of an interspinous device.

FIGS. 28A and 28B show yet another embodiment of an interspinous device.

FIG. 29 shows yet another embodiment of an interspinous device.

FIGS. 30A, 30B, 31A, and 31B show cross-sectional views of interspinousdevices attached to bone.

FIG. 32 shows a bone clamp that can be used to clamp the superior andinferior surface of the lamina on each side of the spinous process.

FIGS. 33A and 33B show another embodiment of an interspinous device.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view of a device 105 that is configured forplacement between the spinous processes of two adjacent vertebralbodies. The device 105 includes a spacer region or central region 110that is sized and shaped to fit between the spinous processes of the twoadjacent vertebral bodies. The device 105 further includes at least oneattachment region 115 that is adapted to attach and anchor onto thespinous process of at least one of the vertebral bodies. The centralregion 110 can have a variety of shapes and sizes for placement betweenthe spinous processes. The attachment region 115 can also have varioussizes and shapes for attachment to the spinous processes. For clarity ofillustration, the vertebral bodies are represented schematically andthose skilled in the art will appreciate that actual vertebral bodiesinclude anatomical details not shown in FIG. 1.

FIG. 2 shows perspective, top, front, and side views of the device 105of FIG. 1. The central region 110 is sized and shaped to fit between thespinous processes of the two adjacent vertebral bodies. In this regard,the central region 110 is shown as a rectangular body, although thecentral region 110 can be spherical, elliptical, oval, or any othershape that fits between the spinous processes. The device preferably hasa distal protrusion 130 that at least partially extends onto either sideof the adjacent spinous process. The attachment region 115 includes anupper wall 210 having a borehole 215 for receipt of a fastener such as abone screw. The inferior surface of the attachment region 115 may befurther grooved or otherwise textured to provide increased bone contactand resistance to rotation. One or more anchor protrusions, such asflaps 220, extend downwardly from the upper wall 210 or may extendbackwards to at least partially extends onto either side of the spinousprocess to which the device is attached. While shown attached to theinferior spinous process, the device may be alternatively attached tothe spinous process above the implanted inter-spinous space (that is,the superior spinous process).

FIG. 3 shows a pair of devices 105 at adjacent vertebral segments. Eachdevice 105 is implanted relative to the vertebral bodies such that twoside flaps 220 straddle the spinous process and aid in attaching thedevice 105 onto the spinous process. The central region 110 ispositioned between the spinous processes. In an alternate embodiment,the flaps 220 can be attached onto the central region 110 to straddle adifferent surface of the spinous process. One or more attachmentscrew(s) 305 can be inserted through the borehole for anchoring thedevice 105. The attachment screw(s) may be alternatively (oradditionally) used to anchor onto the side of the spinous processthrough one flap or serve to connect both side flaps so as to completelycross the spinous process from side to side.

An alternative embodiment is shown in FIG. 4A with a different flaparrangement. The side flaps are configured to at least partially extendonto either side of each of the spinous processes. Many different flaparraignments can be configured and devices with various flaparraignments are considered to fall within the general scope of theinvention. Moreover, any surface of the disclosed implants that contactsbony may be further textured to increase frictional bone contact and/orcoated or treated using one of the many known techniques that increasebony ingrowth and osseous integration at the implant-bone interface(such as porous coating, addition of hydroxyapatite coating,incorporation of bone or growth factors and the like).

FIGS. 4B, 4C, and 4D show another embodiment of the device 105 whereinthe device 105 includes a cavity 405 for receipt of a bone graft orsegment 410. In the embodiment of FIGS. 4B-4D, the device 105 includesflaps 220 that extend outward from the central region 110 rather thanextending from the attachment region 115 as in the previous embodiment.In addition, the device 105 includes a borehole 415 for receipt of afixation device 420, such as a screw, that fixates the bone graft 410 tothe device 105.

FIG. 5 shows the device 105 of FIGS. 4B-4D attached onto the spinousprocess between vertebral bodies. During implantation, the bony surfaceof the spinous process that comes into contact with the bone graft 410of the device 105 is decorticated and cut so as provide a suitablesurface for bone growth and fusion. Interface 520 marks the area ofapposition of decorticated spinous process surface and the bone graftportion of the implant.

An exemplary method of implanting the device 105 is now described withreference to FIGS. 6-8. The method of implantations is described using aparticular embodiment of the device 110 although it should beappreciated that the method of implantation can be used with any of thedevice embodiments. The implantation method uses distraction screws anda distractor device to standardize the extent of vertebral distractionand hasten device placement. FIG. 6A shows a pair of distraction screws505 and 510 positioned adjacent the vertebral bodies. The distractionscrews 505 and 510 include shanks that can be fixated into the spinousprocesses. In one embodiment, at least one screw is optionally amulti-segmental screw that can be detached into two or more segmentsafter it is attached to the spinous process.

FIG. 6B shows the distraction screws 505 and 520 attached to the spinousprocesses of the vertebral bodies and a distractor device 605 mounted onthe distractor screws. The distraction device 605 includes a platformthat can be actuated using an actuator 610 to apply a distraction forceto the distraction screws 505 and 510. Upon actuation of the actuator610, the platform exerts a distraction force to separate the distractionscrews. The distraction can be maintained while the implant is placedbetween them, as described below. The distractor can include anindicator 615 that is capable of measuring the force of distractionproviding an indication as to the amount of distraction force beingapplied (discussed below). In this way, the extent of distraction isstandardized across patients of differing anatomy and is no longerdetermined by subjective “feel” on the part of the operating surgeon.

With the distraction device 605 in place and the segment appropriatelydistracted, the distance between the two spinous processes is measuredand a device 105 of sufficient size is chosen based on the measureddistance. The device 105 is lowered into position such that the centralregion 110 is located between the distracted spinous processes. Thedistraction device is then removed and the central region 110 of thedevice 105 maintains the spinous process in the distracted position.FIG. 7A shows the device 105 positioned between the vertebral bodieswith the distraction screws 505 and 510 still attached to the vertebralbodies. The distraction screw 505 includes a proximal region that can beunattached from the shank of the distraction screw.

Next, the proximal region is removed from the shank of the distractionscrew 505 and the distraction screw 510 is completely removed from thevertebral body. FIG. 7B shows the device 105 positioned between thevertebral bodies with a portion 805 of the distraction screw 505extending upwardly through an opening 810, such as a hole or slot, inthe device 505. Thus, the portion 805 and the attachment region 115 ofthe device 105 are both attached to the spinous process. With referenceto FIG. 8, a retainer, such as a nut 905, is coupled to the portion 805and used to lock the attachment region 115 of the device 105 onto theportion 805 and to the underlying spinous process. As mentioned, theother distraction screw is removed in its entirety. The implantationprocedure provides a fast, reliable and reproducible method ofinterspinous implant placement.

FIG. 9 shows a magnified view of one end of the distraction device orwhile FIG. 10 illustrates a sectional view through that end. The forcemeasurement adapter is shown. With rotation of actuator 610 and theattached leadscrew 611, the two protrusions 625 and 630 (that housedistraction screws 505 and 510) of the distraction platform areseparated and the force of distraction is transmitted onto the containeddistraction screws. As shown in FIG. 10, leadscrew 611 is surrounded byspring 614 and the leadscrew engages pointer 617. As leadscrew 611 turnsand members 625 and 630 are distracted, pointer 617 will move relativeto marking 619 in manner directly related to the force of distraction.The hatch markings 619 may provide an actual measure of the distractionforce in a recognized physical unit or simply give an arbitrary number,letter, or designation to which the operator would distract thevertebral bodies. Using this feature, the force of distraction appliedduring the procedure can be standardized.

FIGS. 11A and 11B illustrate an optional step within the implantationprocedure. After vertebral distraction but before device implantation,the surgeon may directly decompress the nerve elements by removing asmall segment of bone and ligament. The application of distractionbefore boney resection better defines the anatomical landmarks andallows the surgeon to precisely define the compressive elements. Usingthe pre-distraction technique, the decompression is more preciselytailored to the individual patient and the extent of resection issignificantly reduced. The extent of decompression illustrated issubstantially less than traditional laminectomy. FIG. 11A shows aschematic representation of an intact spinal level consisting of twovertebral bodies A & B. FIG. 11B shows the resection performed on oneside. For diagrammatic simplicity, the distraction screws anddistraction device are not shown. However, in actual practice, theresection is performed with the devices in place. With respect to FIG.11B, the decompression is performed by removal of a small segment of theinferior aspect of the superior lamina 655 and of the inferior facetsurface of the superior vertebra as well as a small segment of thesuperior aspect of the inferior lamina 665 and of the superior facetsurface of the inferior vertebra.

FIGS. 12 & 13 illustrate an additional embodiment wherein the implantcan expand and vary in size. The device 2205 has two component members2210 and 2215 that are joined by a joining pin 2220. Member 2210contains threaded bore 2212 that accepts complimentary threaded screw2214. Member 2215 has protrusion 2230 facing member 2210 and engagableby one end of threaded screw 2214. In assembly, as shown in FIG. 12A,screw 2214 is positioned within bore 2212 such that one end of the screwabuts protrusion 2230 of member 2215. With the advancement of screw 2214relative to bore 2212, member 2215 is rotated in the direction R aboutthe axis of joining pin 2220. In this way, the device is lengthened. Inuse, the device can be placed with a distractor, as previouslydiscussed, or it can be placed into the implantation site withoutdistraction and then expanded to the desired length. With the latterimplantation technique, the implant is effectively used as thedistraction device. FIG. 13 shows the implanted device.

FIGS. 14 to 18 illustrate two additional mechanisms that will produceexpandable implants. FIG. 14A shows the first implant mechanism. Thedevice may be directly attached to a spinous process, as previouslyillustrated for other embodiments (attachment member not shown), or itmay be fitted with side protrusion and then left to reside freelybetween two adjacent spinous processes. The latter embodiment is shownin FIG. 14B with the side protrusions closed and in FIG. 14C with sideprotrusions open. The component members are shown in FIGS. 15A and 15B.The device consists of two segments 2505 and 2510 that are attached byrails 2515 and complimentary cut-outs. With actuation of screw member2520, barrel member 2524 is advance along the inclined surface 2530 ofmember 2505 and the device is expanded as shown in FIGS. 16A and 16B.FIG. 17 shows a cam-driven mechanism for device expansion. Asillustrated in FIGS. 18 A and 18B, the device expands as the actuatingscrew and attached cam are rotated.

Another embodiment is shown in FIGS. 19 to 21. While the device can beconfigured to attach onto the spinous process as previously illustratedfor other embodiments, it has expandable side members that will retainit within the interspinous space without attached to bone. Device 2605has four side members 2617 that rotatably deploy with advancement oflocking member 2610. While not illustrated, the central post 2615 hascircumferentially-placed teeth or protrusions that interact with thecomplimentary teeth or protrusions on the outer wall of bore 2612 oflocking member 2610 so as form a ratchet-like locking mechanism. Asshown in FIGS. 20 and 21, side members rotate with advancement of member2610 and the ratchet feature keeps the side members in the deployedstate. In use, the device is preferably placed into the interspinousspace after spinous process distraction and the side members are thenopened. With deployment, each of spinous process is contained within aspace 2632 between a pair of side members.

FIGS. 22 to 27 show several embodiments that attach onto both spinousprocesses. In addition to limiting vertebral extension, these devicescan also control the vertebral motion in anterior flexion, lateralflexion and rotation. That is, with attachment to both spinousprocesses, the device can be used to modulate the motion characteristicsand stabilize the segment in all planes. FIG. 22 shows a rigidembodiment 1001 that can be used to immobilize the motion segment. FIG.23 shows a dynamic device embodiment wherein an elongated member thatincludes a first attachment region 1510 and a second attachment region1520. Both attachment regions include an interface for receiving afastener such as a bone screw 305. The interface in the first attachmentregion 1510 is a circular borehole while the interface in the secondattachment region 1520 is an elongated slot 1525. The screw 305 and theattached spinous process can move along a distance defined by the lengthof the slot to permit relative movement between the two spinousprocesses to which the device 105 is attached. The elongated slot 1525can include or be coupled to a mechanism that permits, but elasticallyresists, screw movement within the slot. In this way, the vertebras areallowed to move when force is applied but they return to the neutralposition when the force has dissipated.

FIG. 24 shows another embodiment of the interspinous device 105 thatpermits relative movement between the vertebral bodies. The device 105includes a first attachment region 1605 and a second attachment region1610 that are movably attached to one another via a sliding connection1615. The first and second attachment regions can move relative to oneanother when a force is exerted onto the device or the attachedvertebral bodies. The device may include a mechanism that biases thefirst and second attachment regions toward a neutral position relativeto one another. When the force producing movement dissipates, the deviceelastically returns the vertebras to the neutral position.

FIG. 25 shows another embodiment of an interspinous device 105 thatincludes first and second attachment regions 1705 and 1710 that aremovably attached to one another. FIG. 26A shows an exploded view of thedevice 105 of FIG. 25. FIG. 26B shows a cross-sectional view of thedevice of FIG. 25. The first and second attachment regions 1705 aremovably linked to one another via a linking member 1720 that extendsthrough a space 1905. An elastic member or material is placed on eitherside of bar 1910 within space 1905. The elastic member/material resistsmovement of the linking member 1720 to thereby resist relative movementbetween the first and second attachment regions 1705 and 1710. A member1920 (such as Belleville washer) resists the movement of a head of thelinking member 1720. Thus, the device is biased toward a neutralposition wherein the first and second attachment regions are positionedin a predetermined location relative to one another. When the forceproducing movement between the first and second attachment regiondissipates, the device elastically returns the vertebras to the neutralposition.

FIG. 27 shows another embodiment of an interspinous device 105. Thedevice 105 includes a first attachment region 1010 and a secondattachment region 1005 that each attach to respective spinous processesof upper and lower vertebral bodies. The device 105 further includes acentral region 1015 positioned between the attachment regions 1005 and1010. The central region 1015 is positioned between the spinousprocesses in the implanted device. The central region is adapted toprovide a range of relative movement between the first and secondattachment regions. Thus, the central region can resiliently deform toprovide such movement. In the illustrated embodiment, the central region1015 includes a bellows-like structure that can alternately expand andretract to permit relative movement between the spinous processes. It isunderstood that one of ordinary skill in the art can fashion comparablerestraining using alternative configurations that employ springs,bellows, energy absorbing materials such as rubber, urethane, fluidschambers/containers, magnets, magnetic fields and the like.

The embodiments of the devices in FIGS. 22-27 are shown with few sideflaps. However, it is understood that additional flaps that straddle thespinous processes can be readily added to these devices to provideadditional stability. In addition, the bone fasteners may be placed inothers segments of the spinous process or attach onto the lamia oneither side of the spinous processes. FIG. 28A shows an additionalembodiment where screws or similar fasteners may be additionallyattached onto the sides of the spinous processes. FIG. 28B shows across-sectional view of a bone screw 1305 extending through the side ofa spinous process SP. The device 105 of FIGS. 28A and 28B includeattachment sections 115 having upper walls and flaps that extenddownwardly to provide a substantial “U” shape that fits over the spinousprocess. As shown, section 115 may also have an additional bore forscrew placement along the long axis of the spinous process.

In FIGS. 29 to 32 additional methods of device fixation onto bone areillustrated. FIG. 29 shows another embodiment of an interspinous device105. The device includes a malleable central region 2910 positionedbetween a pair of attachment regions 2915. The attachment regions 2915include boreholes 2920 that receive bone screws. The bone screws can befixated in the laminal segment of an underlying vertebral body. Thecentral region 2910 is malleable and can take on other shapes to permitmovement between the attached vertebral bodies. FIG. 30A showscross-sectional view of two devices of FIG. 29 attached to bone. In FIG.30B, the screw trajectory extends along the axis of the spinous process.In FIG. 30A, the screw trajectory extends along the axis of lamia boneand is contrasted to the trajectory of the spinous process screws (ofprior embodiments) that is shown in FIG. 30B.

The placement of the device of FIG. 29 can be performed as a minimallyinvasive surgical procedure. The spinous processes of the operativelevel are identified and a skin incision is made between them. The softtissue is dissected off of the side of the spinous process to which theinterspinous device is to be attached. The device is then placed throughthe incision into the depth of the wound and onto the side of thespinous process. Percutaneous placement of the lamina screw is thenperformed. The screw is placed through a stab wound in the skin, acrossthe underlying soft tissue, through one of the device's bore holes andinto the underlying lamina.

Additional screw trajectories are illustrated in FIG. 31. Unlike thelamina screw of FIG. 30A, the screw trajectory of FIG. 31A preferablyaims the screw tip towards the vertebral midline M. In FIG. 31B, screw3102 is anchored into the midline of the anterior lip of the superioraspect of the spinous process. This segment of bone is particularlystrong and well situated for fastener placement. FIG. 32 illustrates abone clamp that can be used to clamp the superior and inferior surfaceof the lamina on each side of the spinous process. The precedingattachment methods can be adapted for use with any of the illustratedembodiments.

FIGS. 33A and 33B show yet another embodiment of an interspinous device105. The device 105 includes a malleable central region 2615 attached toa pair of attachment regions 2620 and 2625. The attachment regions areattached to a pair of screws 305 that are attached the spinousprocesses. The central region 2615 limits the extent of vertebralextension at the implanted level. The malleable nature of the deviceresists vertebral extension and rotation. The device also resistsanterior or posterior displacement of one vertebral level relative tothe other. While depicted as being comprised of three separate membersfor illustration, device 105 is preferably manufactured and used as asingle unit. The central region 2615 comprises a spring-like structureformed of an elongated member that has a coiled configuration. The endsof the elongated members are attached to the spinous processes. Thecentral region extends along an axis that is oriented between thespinous processes.

Any of the device embodiments can be made of any biologically adaptableor compatible materials. Materials considered acceptable for biologicalimplantation are well known and include, but are not limited to,stainless steel, titanium, tantalum, combination metallic alloys,various plastics, resins, ceramics, biologically absorbable materialsand the like. Any components may be also coated/made withosteo-conductive (such as deminerized bone matrix, hydroxyapatite, andthe like) and/or osteo-inductive (such as Transforming Growth Factor“TGF-B,” Platelet-Derived Growth Factor “PDGF,” Bone-Morphogenic Protein“BMP,” and the like) bio-active materials that promote bone formation.Further, the outer surface of the bone screw assemblies may be made witha porous ingrowth surface (such as titanium wire mesh, plasma-sprayedtitanium, tantalum, porous CoCr, and the like), provided with abioactive coating, made using tantalum, and/or helical rosette carbonnanotubes (or other carbon nanotube-based coating) in order to promotebone in-growth or establish a mineralized connection between the boneand the implant, and reduce the likelihood of implant loosening. Lastly,the screw assemblies, inter-connectors and/or any component can also beentirely or partially made of a shape memory material or otherdeformable material.

Although embodiments of various methods and devices are described hereinin detail with reference to certain versions, it should be appreciatedthat other versions, embodiments, methods of use, and combinationsthereof are also possible. Therefore the spirit and scope of theappended claims should not be limited to the description of theembodiments contained herein.

What is claimed is:
 1. An orthopedic device configured to be at leastpartially implanted within an inter-spinous space, said inter-spinousspace being bordered by at least a superior spinous process and aninferior spinous process, said orthopedic device comprising: a firstlongitudinal member having a length greater than a distance from aninferior end of said superior spinous process to a superior end of saidinferior spinous process; a second longitudinal member substantiallyaligned to face said first longitudinal member and having a lengthgreater than said distance; a transverse member configured to integrallydiverge from said first longitudinal member, said transverse memberextending towards and at least contacting said second longitudinalmember; and a cavity at least partially bounded by said firstlongitudinal member and said transverse member, said cavity housing abone forming material and configured to open directly onto one of saidspinous processes; at least one rigid bone fixation member that extendsfrom one of said longitudinal members and fixates onto one of saidspinous processes; wherein at least said first and second longitudinalmembers and said transverse member are formed by a non-osteogenicmaterial.
 2. The orthopedic device of claim 1, wherein at least oneexternal surface of said orthopedic device is textured in order topromote fixation onto an adjacent bone.
 3. The orthopedic device ofclaim 1, wherein said orthopedic device is at least partially comprisedof titanium.
 4. The orthopedic device of claim 1, wherein saidorthopedic device is at least partially comprised of a plastic material.5. An orthopedic device configured to be positioned at least partiallywithin an inter-spinous space, said inter-spinous space being borderedat least by a superior spinous process and an inferior spinous process,said orthopedic implant comprising: a first longitudinal member having alength greater than a distance from an inferior end of said superiorspinous process to a superior end of said inferior spinous process; asecond longitudinal member substantially aligned to face said firstlongitudinal member and having a length greater than said distance; anda first and a second transverse member configured to integrally divergefrom said first longitudinal member, said first and second transversemembers being comprised of a non-osteoinductive material, and beingsubstantially aligned to face one another and to define a cavitytherebetween, said cavity housing a bone forming material and configuredto open directly onto one of said spinous processes; and at least onerigid bone fixation member that extends from one of said longitudinalmembers and fixates onto one of said spinous processes.
 6. Theorthopedic device of claim 5, wherein at least one external surface ofsaid orthopedic device is textured in order to promote fixation onto anadjacent bone.
 7. The orthopedic device of claim 5, wherein saidorthopedic device is at least partially comprised of titanium.
 8. Theorthopedic device of claim 5, wherein said orthopedic device is at leastpartially comprised of a plastic material.
 9. A method for placement ofan orthopedic device within an inter-spinous space, said inter-spinousspace being bordered at least by a superior spinous process and aninferior spinous process, comprising: decorticating a bony surface of atleast a portion of at least one of said spinous processes; placing afirst longitudinal member of said orthopedic device having a lengthgreater than a distance from an inferior end of said superior spinousprocess to a superior end of said inferior spinous process, such that itabuts a superior aspect of said inferior spinous process; placing asecond longitudinal member of said orthopedic device having a lengthgreater than said distance such that it substantially faces said firstlongitudinal member; positioning a cavity of said orthopedic device atleast partially within said inter-spinous space, said cavity formedbetween said first longitudinal member and a transverse member of saidorthopedic device that extends from said first longitudinal member andtowards said second longitudinal member, said cavity housing a boneforming material therein; and aligning an opening of said cavity tocontact said decorticated bony surface; wherein at least one rigid bonefixation member extends from a longitudinal member and fixates onto oneof said spinous processes; and wherein at least said first and secondlongitudinal members and said transverse member are formed by anon-osteogenic material.
 10. The method of claim 9, further comprisingcausing at least one external surface of said orthopedic device to betextured in order to fixate onto an adjacent bone.
 11. The method ofclaim 9, further comprising causing at least a portion of saidorthopedic device to be manufactured from a metallic material.
 12. Themethod of claim 9, further comprising causing at least a portion of saidorthopedic device to be manufactured from a plastic material.